thornton



(No Model.) 2 SheetsSheet 2.

J. E. THORNTON.

PHOTOGRAPHIG SHUTTER. v No. 482,854. Patented Sept. 20, 1892.

FIGI2.

FIG 5. M:

WlTNESSES INVENTUR M. 0PM by W (in addition to retaining the blind inposition UNITED STATES PATENT OFFICE.

JOHN E. THORNTON, OF MANCHESTER, ENGLAND, ASSIGN OR OF ONE-HALF TO EDGARPIOKARD, OF SAME PLACE.

IC SHUTTER.

SPECIFICATION forming part of Letters Patent No. 482,854, datedSeptember 20, 1892.

Application filed November 3, 1890. Serial No. 370,208. (No model.)Patented in England September 27, 1886, No. 12,238.

To aZZ whom it may concern:

Be it known that 1, JOHN EDWARD THORN- TON, manufacturer of photographicapparatus, asubject of the Queen of England, and a residentofManchester, in the county of Lancaster, England, have invented a new anduseful Photographic Shutter, (for which I have obtained Letters Patentin Great Britain, No. 12,238, bearing date September 27, 1886,) of whichthe following is a specification.

The object of the invention is to provide a shutter for photographiccameras which,while capable of being used as an instantaneous shutter,can also be set or adjusted as a timeshutter, in which the duration ofthe exposure may extend to any desired length of time. It refers to thatclass of shutters in which a spring -blind of Mackintosh cloth or otheropaque material is used, the blind being attached at one end to aspring-driven roller and at the other to a winding-roller, and formedwith an aperture or opening in the center, through which light enters tothe lens as the blind moves across the front of it.

The invention consists, essentially, in applying to or combining withthe gear of the winding-roller an adjustable detent or stop capable ofbeing set in two positions, which when drawn up) will when set in thefirst position by one movement or stroke of the detent-lever stop orarrest the movement of the blind when full open and shall instantlyrelease it and allow it to close at a second stroke or movement of thelever, thus effecting a time-exposure, and when moved to the secondposition shall allow of a so-called instantaneous exposure, not stoppingor arresting the movement of the blind at all when full open. It will befully described with reference to the accompanying drawings.

Figure 1 is a perspective View of a photo graphic shutter with theinvention applied thereto; Fig. 2, a sectional elevation of the shutter,showing the position of the blind; Fig. 3, an extended view of the blindand blind-rollers, and Fig. 4 detail views of the detent-lever E and thespring E.

The shutter is constructed in the usual way with a blind A, of the shapeshown in Fig. 3, 5o inclosed in a box or case B. The blind is in theform of a spring-blind, mounted upon a winding-roller a at one end andupon a spring driven roller a at the other end, and is provided with anopening or aperture A in the center for the passage of light to the lensas the blind travels pastit. Theblind is wound up upon the roller a by acord J, passing over a small pulley j, or by a projecting knob orotherwise.

On the end of the winding-roller a which projects through the side ofthe inclosing case B is placed a small wheel or pinion O,preferablygearing into a larger wheel or pinion D. In one of thesewheels-preferablyin the face of the larger wheel Dare affixed two studs0 (l, by means of which the rotation of the wheel D can be arrested. Inclose proximity to the wheel D is a movable lever E, carrying a detentor stop a, which may be cut into the lever, as shown, or project fromthe side or top of it and which engages with the studs 0 d on the faceof the wheel D. The lever E is arranged to move laterally, being pivotedat 6, so as to adjust the position of the detent e relatively to thestuds 0 and d.

The lever E has a movement in two directionshorizontally and vertically.When in the position shown in the drawings, with the finger i pointingto the index-letter I, if raised it is clear of both studs 0 d and thetoothed disk D and the winding-roller pinion O haveanuninterruptedmovement. \Vhen,however, the leverE is moved to the leftuntil the finger 11 points to the index-letter T, the raising of thelever only releases the stud c from the detent cand the stud d as thedisk moves comes in contact with the detent e and all movement isarrested thereby. The lever E is held in position and drawn back whenraised by the spring E.

The position of the stud d relatively to the blind A is such that whenin contact with the detent e of the detent-leverE the aperture A of theblind is opposite to the lens or lens-ap- 5 erture in the shutter-caseB. Consequently when the stud d is arrested by the detent e the blind Ais arrested when full open and remains so for any length of time,according to the will of the operator, and the position of the stud 0relative to the blind A is such that when the blind is fully wound upupon the winding-roller a the stud c engages with the detent e. The stud(Z is bent or of inverted- L shape to allow of its passing over or clearof the detent e and detent-lever E when the lever is at rest.

On the toothed disk D is placed a third stud c. This stud is shorterthan either of the other two and serves to engage with detent c and holdthe blind with the aperture opposite to the lens for focusing or similarpurposes. In the position shown in the drawings-in advance of the studd-this third stud 0 does not interfere with the movement of the disk Dwhen released, as it passes under the edge of the detent-lever beforethat lever can fall again. It might, however, be placed at the otherside of the stud d, with the stud cl slightly in advance of it, in whichcase the detent 6 would engage with it after the movement of the disk Dhad been arrested by the stud d coming in contact therewith. The lever Ewould then have to be raised a second time before the blind A wouldcontinue its travel.

Instead of applying the stud c, engaging with the detent e, to retainthe blind A in position when fully wound up, a separate pawl or catchengaging with the teeth may be employed, which will be withdrawn by themovement of the detent-lever E. It will be evident, also, that theinterposition of the wheels 0 and D are not essential to the working ofthe invention, as the toothed disk D might be replaced by a straighttoothed rack, or both might be dispensed with and a pin or stud beinserted into the projecting end of the winding-roller Ct to engagedirect with the detent e, and the detent-lever E may be arranged to moveeither horizontally or vertically to release the blind A.

The detent-lever E is moved to actuate the blind by means of a pneumaticbulb F, which is expanded on pressure being applied to a ball or bulb Gat the other end of the tube H, or it maybe raised by a small pistonactuated by a pneumatic ball or by a cord attached to one end of thelever.

In operation the blind is wound up upon the roller a off thespring-driven roller ct by the cord J on the pulleyj until the stud 0engages with the detent e. To effect a time exposure or control theduration of the exposure, the lever E is moved to the left until thepoiuter istands opposite to the indexletter T. The ball G is compressedby the hand of the operator, expanding the bulb F and lifting the leverE, until the detent e is clear of the stud c. The blind is thusreleased, and the spring in the roller a, which is tightened by thewinding up of the blind on the other roller 0., draws it back again. Itsprogress is arrested by the cranked or bent part of the stud d coming incontact with the detent 6 when the aperture A is opposite to the lens.As soon as the pressure on the ball G is released the lever E fallsagain and the blind is allowed to resume its travel. Thus the durationof exposure is subject to the length of time the ball G is heldcompressed. By altering the position of the third stud c, ashereinbefore described, the lever E after the detent 0 had arrested thestud 0 would on the release of pressure fall and engage with the studc', and a second compression of the ball G would be necessary before theblind would be released to resume its travel, and in this case theduration of the exposure would depend upon the length of time allowed toelapse between the first and second compression of the ball G".

To effect an instantaneous exposure, the lever E is moved to the rightuntil the pointer i stands opposite the index-letter I, which draws thedetent 6 clear of the stud (Z. The ball G is compressed, as before, thebulb F expanded, the lever E raised, and the blind, being released, israpidly drawn from the winding-roller a to the spring roller a withoutstopping.

Having now described the invention, what I claim is 1. In a photographicshutter constructed with a spring-driven blind mounted upon a roller a,the combination, with a rotating disk D, geared to a pinion O andprovided with a projecting stud d, of the movable adjustable stop-leverE, provided with the detent or stop a to engage with the said stud,substantially as and for the purposes described.

2. In a photographic shutter having a spring-driven blind, thecombination, with the rotating disk D, carrying projecting pins or studs0, c, and d, of the detent lever E, provided with the detent c, whichengages with the said studs, substantially as described.

3. In a photographic shutter, the combination, with the spring-drivenblind A, windingroller a, and pinion O, of the toothed disk having theprojecting pin or stud (Z, the detentlever E, having the detent or stop(-2, which engages with the projecting pin, and the pneumatic bulb E andball G, by which the detentlever is moved, substantially as described.

t. In a photographic shutter, the combination, with the spring-drivenblind A, winding roller a, carrier-pinion O, and toothed disk D, havingstuds 0 d 0 upon its face, of the adjustable detent-lever E, with detente, which engages with the said studs and the pneumatic bulb F and ballG, substantially as described.

5. The combination of the spring-driven blind A, having aperature A,mounted in the case B on a spring-roller a and winding-roller a, thepinion O, affixed to the end of the winding-roller, the toothed disk D,carrying studs 0 d c, the adjustable lever E, carrying detent e, whichengages with the studs on the diskD name to this specification, in thepresence of and arrests the progress of the blind, and the twosubscribing witnesses, this 22d day of Ocpneumatic bulb F, operated bythe ball G, tober, 1890.

which moves the detent-lever E to release the J. E. THORNTON- 5 studs onthe disk D, substantially as and for Witnesses:

the purposes described. J. OWDEN OBRIEN,

In testimony whereof I have. signed my CHARLES OVENDALE.

